Friction type continuously variable transmission

ABSTRACT

A friction type continuously variable transmission has double cones kept in contact with an input shaft and a drive cone and is capable of transmitting the rotation of the input shaft to an output shaft so that the output shaft rotates at a higher speed than the input shaft. A mechanism is provided for preventing the double cones from rotating about the input shaft and from coming off of their support shafts. A stay is mounted on a carrier supporting the double cones. The stay carries a guide roller bearing received in a guide fixed to a housing of the transmission. The stay thus prevents the rotation of the carrier while allowing only its axial movement. A stopper surface is provided at one end of the guide to restrict the axial movement of the carrier within a predetermined range.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to a friction type continuously variabletransmission for variably adjusting the rotational speed of a driveshaft such as an impeller of a centrifugal blower, a centrifugalcompressor or a radial turbine.

2. Background Art

Unexamined Japanese Utility Model Publication 3-5948 discloses aconventional friction type variable transmission capable of rotating anoutput shaft at a constant speed in spite of the change of therotational speed of an input shaft by variably adjusting a shaft fordriving a high-speed rotary member such as an impeller.

FIG. 14 shows this transmission. It has an input shaft 2 and an outputshaft 3 supported by bearings in a housing 1 at both ends so as to becoaxial with each other. A plurality of double cones 4 are arrangedaround the output shaft 3. They are rotatably mounted on support shafts6 fixed to a carrier 5 axially movably mounted on the output shaft 3.

The input shaft 2 has at its inner end an integral input ring 7 kept incontact with one conical surface 4a of each double cone 4. The outputshaft 3 carries at its inner end a drive cone 8 that contacts the otherconical surface 4b of each double cone 4.

A holder 10 is fixed to an outer ring of a bearing 9 supporting theinput shaft 2. A plurality of springs 11 are disposed circumferentiallybetween the holder 10 and the housing 1 to axially pull the input shaft2 via the bearing 9. As the input shaft 2 is pulled by the springs 11,the double cones 4 and thus the output shaft 3 are also pulled in thesame direction. But since the output shaft 3 is fixed to the housing, aforce that reacts to the biasing force of the springs 11 is produced, sothat the input shaft and the output shaft are subjected to a tensileforce that tends to pull them away from each other.

When the input shaft 2 is rotated, its rotation is transmitted throughthe input ring 7 to the double cones 4, and then through the drive cone8 to the output shaft 3. An impeller mounted on the output shaft 3 isthus rotated. To change the rotational speed of the output shaft 3, thedouble cones 4 are moved axially of the output shaft 3 by controlling acarrier moving means 12 for axially moving the carrier 5.

In this way, the rotation of the input shaft 2 is transmitted throughthe input ring 7 to the double cones 4, which are pressed against theinput ring 7 under the force of the springs 11. The rotational speed ofthe output shaft 3 is determined by the axial position of the doublecones 4. Thus, it is important that the carrier 5 supporting the doublecones 4 and its inner guide 13 be axially movable with sufficientsmoothness.

In this respect, the conventional carrier moving means 12 for axiallymoving the carrier 5 is a rack-and-pinion mechanism, which cannotprevent the rotation of the carrier 5. Thus, when the input shaft 2 isrotated, the double cones 4 tend to rotate about the center axis of thecarrier guide 13 while rotating about their own axes. The rotation ofthe double cones 4 about the carrier guide 13 may have detrimentaleffects, such as an abrupt change in the speed ratio or the separationof the joint between the carrier moving means 12 and the carrier 5.

If the carrier 5 moves axially out of the permissible range, the doublecones 4 will disengage from the drive cone 8 or the input ring 7, makingthe transmission of torque impossible.

If the input shaft is rotated at a high speed, the double cones 4,rotatably mounted on the support shafts 6 protruding from the carrier 5,are rotated at a correspondingly high speed, so that they may come offof the support shafts 6 because of their own inertia and consequentlydisengage from the drive cone 8 and the input ring 7.

In this arrangement, whenever the input shaft 2 is rotating, itsrotation is transmitted through the integral input ring 7 to the doublecones 4 because the input ring 7 is always pressed against the doublecones 4 under the force of the springs 11. The double cones 4 are keptrotating and thus the output shaft 3 is thus rotated whenever the inputshaft 2 is rotating.

Suppose now that this friction type variable transmission is mounted onan automobile as a speed-up device. Its input shaft 2 is coupled to theengine crankshaft directly or through a pulley or a belt to increase orreduce its speed before being transmitted to the input shaft. While theengine is running and thus the crankshaft is rotating, the input shaft 2is rotated. As mentioned above, while the input shaft 2 is rotating, theoutput shaft 3 is always rotated.

When used for this application, the output shaft 3 need not be rotatedwhile the engine revolving speed is within a certain range. But it isstructurally impossible to stop the rotation of the output shaft 3 aslong as the input shaft 2 is rotating. Since the output shaft isunnecessarily rotated, engine power is wasted.

Since the output shaft and other rotary parts of the friction typevariable transmission are always rotated even while they need not berotated, they tend to wear quickly, thus shortening the life of theentire transmission.

FIG. 15 shows another conventional transmission which, in order toincrease the rotational speed of the output shaft compared to the inputrotational speed, includes a planetary gear unit 20 coupled to the inputshaft 2 of the friction type variable transmission unit shown in FIG.14. The gear unit 20 increases and transmits the rotation of its inputshaft 25 to the input shaft 2 of the transmission unit.

The planetary gear unit 20 comprises an internal gear 22, a plurality ofplanetary gears 23 provided inside and meshing with the internal gear22, a carrier 24 coupled to the input shaft 25 and supporting theplanetary gears 23, and a sun gear 26 meshing with the planetary gears23 and fixed to the input shaft 2 of the transmission unit.

When the input shaft 25 of the planetary gear unit 20 rotates, theplanetary gears 23, meshing with the internal gear 22, begin rotatingabout the sun gear 26 while rotating about their own axes. The inputshaft 2 of the transmission unit is thus rotated at an increased speed,so that the impeller 14 mounted on the output shaft 3 rotates at a highspeed.

In order to lubricate the inner parts of the transmission unit and theplanetary gear unit 20 in an optimum way, it is preferable to circulatelubricant through the transmission. Heretofore, in order to circulatelubricating oil, an oil pump was provided outside the transmission tocirculate lubricating oil through an external pipes connecting the oilpump to inner parts of the transmission which have to be lubricated.

In this arrangement, since the external pipes and the oil pump areprovided outside the housing of the transmission, the size of the entiredevice is rather massive, so that a large installation space is needed.

Today, smaller friction type variable transmissions are required.

In an arrangement in which the parts in the transmission are lubricatedby dripping oil from the top of the housing, no optimum lubrication ofthese parts is possible. Namely, if the amount of oil supplied to theseparts is scarce, they cannot be lubricated sufficiently. If too much oilis supplied, oil leakage may occur.

Moreover, with this arrangement, lubricating oil tends to be carriedaway by the flow of air in the housing caused by the rotating doublecones 4 and input ring 7, making it even more difficult to supply asufficient amount of lubricating oil to desired locations.

SUMMARY OF THE INVENTION

A first object of this invention is to provide a friction type variabletransmission having means for restricting the movement of its doublecones and carrier within proper ranges so that it can stably perform itsvariable speed transmission function.

A second object of this invention is to provide a mechanism which canselectively stop the rotation of the transmission without impairing itsfunction as a friction type variable transmission.

A third object of this invention is to provide a friction type variabletransmission having a lubricating oil circulation means which is compactand can circulate lubricating oil smoothly.

According to a first aspect of the invention, there is provided afriction type continuously variable speed transmission comprising aninput shaft, an output shaft and a plurality of double cones kept incontact with both the input shaft and the output shaft for transmittingthe rotation of the input shaft to the output shaft. A carrier isslidably mounted on the output shaft for changing the revolving speed ofthe output shaft by moving the double cones in the axial direction ofthe input shaft. A rotation preventive means is provided for preventingthe rotation of the carrier about the output shaft while allowing itsaxial movement along the output shaft.

According to a second aspect of the invention, there is provided afriction type continuously variable transmission comprising an inputshaft, an output shaft provided coaxially with the input shaft and aplurality of double cones kept in contact with both the input shaft andthe output shaft so as to be movable in the axial direction of the inputand output shafts. A biasing means biases the input shaft away from thedouble cones so that the double cones are pulled by the input shaft andthe output shaft in opposite directions. A clutch is coupled to theinput shaft for selectively transmitting and cutting off a driving forceto the input shaft, and a rotation preventive means is provided betweenthe input shaft of the friction type continuously variable transmissionand the clutch for preventing the rotation of the input shaft relativeto the clutch while allowing axial movement of the input shaft.

According to a third aspect of the invention, there is provided afriction type continuously variable transmission comprising a frictiontype variable transmission unit having a housing and an input member. Agear unit is coupled to the input member and has an input shaft fortransmitting the rotation of the input shaft to the input member. An oiltank is provided below the transmission unit and the gear unit and anoil pump is mounted on the input shaft of the gear unit for suctioningthe lubricating oil in the oil tank. The housing of the transmissionunit is provided with a passage through which the lubricating oilsuctioned by the oil pump is supplied to necessary parts of thetransmission unit.

In the first aspect of the invention, the rotation preventive meansprevents the rotation of the carrier supporting the double cones whileallowing only its axial movement. The double cones are thus preventedfrom rotating around the input shaft.

By providing a stopper for restricting the axial movement of the carrierand/or by providing the support shafts for the double cones withlarge-diameter portions to prevent the double cones from coming off ofthe shafts, it is possible to restrict the movement of the double coneswithin a proper range. This makes it possible to prevent the doublecones from getting out of contact with the input or output shaft.

In the second aspect of the invention, to transmit the driving force tothe input shaft, the input shaft is coupled to the drive source byengaging the clutch. By disengaging the clutch, the input shaft isdisconnected from the driving source, so that no driving force istransmitted to the input shaft.

By coupling the input shaft to the clutch through the rotationpreventive means which allows axial movement of the input shaft, it ispossible to prevent the input shaft from interfering with the clutcheven if it moves axially. This makes it possible to apply the axialforces of the input shaft to the double cones in an optimum way.

In the third aspect of the invention, the lubricating oil in the oiltank is suctioned by the oil pump linked to the input shaft of theplanetary gear unit, and supplied through the passage formed in thehousing to various parts of the transmission. The oil circulated throughthe transmission is returned to the oil tank.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional front view of a first embodimentaccording to a first aspect of the invention.

FIG. 2 is a vertical sectional side view of the same.

FIG. 3 is a vertical sectional front view of a second embodiment.

FIG. 4 is a partial enlarged sectional view of the same.

FIG. 5 is a vertical sectional side view of a third embodiment.

FIG. 6 is a vertical sectional side view of a forth embodiment.

FIG. 7 is a vertical sectional side view of a fifth embodiment.

FIG. 8 is a vertical sectional side view of a sixth embodiment.

FIG. 9 is a vertical sectional view of one embodiment according to asecond aspect of the invention.

FIG. 10 is a vertical sectional view of one embodiment according to athird aspect of the invention.

FIG. 11 is a sectional view taken along line 11--11 of FIG. 10.

FIG. 12 is a vertical sectional view of another embodiment.

FIG. 13 is a partial enlarged sectional view of the same.

FIG. 14 is a vertical sectional view of a conventional device.

FIG. 15 is a vertical sectional view of a conventional device includinga planetary gear unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Now reference is made to the drawings to describe the embodiments ofthis invention. The friction type variable transmission according tothis invention is basically the same in its structure and function asthe conventional device shown in FIG. 14. Thus, the same elements aredenoted by the same numerals and their description is omitted.

FIGS. 1 and 2 show the first embodiment of a first aspect of theinvention. In this embodiment, the carrier 5 is axially slidable along acarrier guide 13 mounted on the housing 1. It has a frontcircumferential tapered surface 5a from which three support shafts 6protrude. A double cone 4 is supported on each support shaft 6. A stay31 extends radially from the outer periphery of the carrier 5 near itsrear end so as not to interfere with the support shafts 6. A rollingbearing as a guide roller bearing 32 is mounted on the free end of thestay 31.

An axial guide 33 is bolted to the rear end face of the housing 1. Ithas a guide hole 34 elongated in the axial direction of the output shaft3. The guide roller bearing 32 is received in the hole 34, which is wideenough for the guide roller bearing 32 to be smoothly rollable in theaxial direction.

A stopper surface 35 is formed at the front end of the guide hole 34. Itprevents, by abutting the guide roller bearing 32, the double cones 4from moving rightwardly in FIG. 1 beyond the range within which they arein contact with the drive cone 8 and the input ring 7.

Now in operation, when the input shaft 2 is rotated and the double cones4 begin to rotate about their axes, a rotating force acts on the carrier5. But the carrier 5 will never actually turn because the guide rollerbearing 32 is received in the guide hole 34. Namely, the carrier 5 andthe double cones 4 are only slid axially by the carrier moving means 12.

If the double cones 4 move rightwardly to the limit of the permissiblerange within which they are in contact with both the drive cone 8 andthe input ring 7, the guide roller bearing 32 abuts the stopper surface35, so that the double cones cannot move rightwardly beyond thepermissible range.

Two or more stays 31 may be provided on the outer periphery of thecarrier 5 of this embodiment.

The guide 33 may be mounted on the inner periphery of the housing 1, oron the carrier guide 13 fixed to the housing 1.

While the stay 31 and the guide 33 are kept in rolling contact with eachother through the guide roller bearing 32 in the embodiment, they may bekept in sliding contact through a sliding member having a small slidefriction coefficient.

FIGS. 3 and 4 show a second embodiment according to the first aspect ofthe invention.

In this embodiment, support shafts 36 protruding from the front end ofthe carrier 5 are inserted in through holes 37 formed in the doublecones 4 to rotatably support the double cones 4 through needle bearings38.

Each support shaft 36 has an end member 39 formed with a flange 40having a larger diameter than the opening of the through hole 37 formedin each double cone 4.

If the double cones 4, being rotated at high speed, are moved axiallyoutwardly along the support shafts 36 due to centrifugal force, theywill abut the large-diameter flange 40 of the end member 39 of eachsupport shaft 36, so that they will never come off of the support shafts36. Namely, the double cones 4 are kept in proper engagement with boththe drive cone 8 and the input ring 7 even while they are rotating at ahigh speed.

FIG. 5 shows a third embodiment of the first aspect of the invention. Inthis embodiment, an L-shaped stay 41 is fixed to the rear end face ofthe housing 1. It carries on its front end another stay 42 extendingtoward the carrier 5.

A guide 43 is fixedly mounted on the outer periphery of the carrier 5.It is formed with an axially extending guide groove 44 in which isslidably received a guide roller bearing 45 mounted on the end of thestay 42.

The carrier 5 is thus guided by the bearing 45 in the guide groove 44 soas to be movable only in the axial direction. Similar to the embodimentof FIG. 1, a stopper surface for limiting the axial movement of thecarrier 5 is provided at the front end of the guide groove 44.

FIG. 6 shows a fourth embodiment according to the first aspect of theinvention. In this embodiment, a guide 51 is fixed to a fixed carrierguide 13. The carrier 5 is slidably mounted on the carrier guide 13. Thecarrier 5 is formed with an axially extending guide groove 52 in whichis received the guide 51 to prevent the carrier 5 from rotating relativeto the carrier guide 13. A stopper surface for limiting the axialmovement of the guide may be provided at the front end of the guidegroove 52.

FIG. 7 shows a fifth embodiment of the first aspect of the invention. Inthis embodiment, a rack holder 53 of the carrier moving means 12 isdesigned so that it can prevent the rotation of the carrier 5.

The carrier moving means 12 comprises a driving means 54, a shaft 55coupled to the driving means 54, a pinion 56 mounted on the shaft 55, arack 57 meshing with the pinion 56, and the rack holder 53 through whichthe rack 57 is fixed to the carrier 5. The rack holder 53 is formed withan axially extending guide groove 58 in its bottom. The carrier guide 13has a guide 59 axially slidably received in the guide groove 58 to allowonly axial movement of the carrier 5 while preventing its rotation.

FIG. 8 shows a sixth embodiment of the first aspect of the invention, inwhich the rotation preventive means comprising the guide and the guidegroove is not provided between the carrier 5 and the carrier guide 13 asin the third and fourth embodiments, but outside the carrier 5.

Namely, an axially extending guide groove 62 is formed in a member 61fixed to a large-diameter portion the carrier guide 13. A guide 63mounted on the outer periphery of the carrier 5 is received in the guidegroove 62 to hold the carrier 5 so as to be slidable in the axialdirection.

FIG. 9 shows the friction type variable transmission embodying a secondaspect of the invention.

This transmission comprises a friction type variable transmission unitmounted in the housing 1, and an electromagnetic clutch 72 coupledthrough a rotation preventive means 71 to the input shaft 2 of thetransmission unit. The electromagnetic clutch 72 has a clutch pulley 73coupled to a driving source (not shown) through a belt.

The friction type variable transmission unit is structurally the same asthose in the previous embodiments. Its description is thus omitted.

The electromagnetic clutch 72 comprises a clutch shaft 74 coupled to theinput shaft 2. The clutch pulley 73 is rotatably mounted around theclutch shaft 74. An electromagnetic clutch plate 75 is provided at oneend of the clutch pulley 73, and an electromagnet 76 is mounted in theclutch pulley 73 at the other end thereof. The electromagnetic clutchplate 75 is axially movably coupled to one end of the clutch shaft 74through splines 77. When the electromagnet 76 is activated, the clutchplate 75 is attracted to the clutch pulley 73, so that the driving forceapplied to the clutch pulley 73 is transmitted through the clutch plate75 to the clutch shaft 74.

The rotation preventive means 71, through which the clutch shaft 74 iscoupled to the input shaft 2 has in one end of the clutch shaft 74 ahollow 78 in which is received the end of the input shaft 2. Axialsplines 79 are formed on the inner surface of the hollow 78 and theouter surface of the end of the input shaft 2 inserted in the hollow 78.By the engagement of splines 79, torque is transmitted between theclutch shaft 74 and the input shaft 2 while they are axially movablerelative to each other.

The splines 79 may be involute splines, i.e., splines having an involutesectional shape, or may be ball-splines, i.e. splines with ballsreceived between the splines.

If this friction type variable transmission is used as a speed increaserfor an automotive engine, the clutch pulley 73 of the electromagneticclutch 72 is coupled to an engine pulley through a belt to transmit therotation of the engine crankshaft to the electromagnetic clutch 72.

Once coupled, the clutch pulley 73 is kept rotated by the engine as longas the engine is running irrespective of whether the variabletransmission is used or not.

In order to increase the engine rotational speed using the friction typevariable transmission, the electromagnet 76 of the electromagneticclutch 72 is activated to attract the electromagnetic clutch plate 75against the clutch pulley 73. Now speed is changed while the rotation ofthe engine is transmitted through the clutch shaft 74 to the input shaft2, and then through the input ring 7, double cones 4 and drive cone 8 tothe output shaft 3.

If the operation of the friction type variable transmission is notneeded while the engine runs, the electromagnetic clutch plate 75 issimply separated from the clutch pulley 73 of the electromagnetic clutch72. In this state, the rotary elements in the friction type variabletransmission, except for the clutch pulley 73, are not rotating, so thatengine power is not wasted. It is possible to reduce the wear of theserotary members, too.

During operation, although the input shaft 2 is axially biased by thesprings 11, the rotation preventive means 71 blocks the input shaft 2from moving toward the clutch shaft 74, so that they will not interferewith each other. Thus, the biasing force of the springs 11 istransmitted to the input shaft 2 and the double cones 4 without fail, sothat the shaft 2 an of the input shaft 2 and the output shaft 3 whichacts on the double cones 4 can be controlled to a predetermined constantlevel.

In this embodiment, the electromagnetic clutch 72 is used to selectivelyconnect and disconnect the input shaft 2 to and from the engine. But amechanical, hydraulic or any other type of clutch having the samefunction may be used instead.

Instead of the rotation preventive means 71, comprising the splinesformed on the input shaft 2 and the clutch shaft 74 by machining, arotation preventive means that are separate from both shafts may beprovided therebetween.

FIGS. 10 and 11 show an embodiment of a third aspect of the invention.The friction type variable transmission of the third aspect of theinvention comprises a friction type variable transmission unit, aplanetary gear unit 20 coupled to the input member of the transmissionunit, and an impeller 14 mounted on the output member of thetransmission unit. The rotation of the planetary gear unit 20 isincreased by its planetary gears and then by the friction type variabletransmission unit to rotate the impeller 14 at high speed.

The friction type variable transmission unit and the planetary gear unit20 are structurally the same as the prior art shown in FIGS. 14 and 15.Thus, like elements are denoted by like numerals and their descriptionis omitted.

In the third invention, as shown in FIG. 10, the transmission unit andthe planetary gear unit 20 are mounted in a common housing la. Its oneend is capped with a closure member 82 carrying a trochoid pump 81 inits center.

The trochoid pump 81 has a rotor coupled to the input shaft 25 of theplanetary gear unit 20. While the input shaft 25 is rotating, the pump81 draws up lubricating oil in an oil tank 83 (to be described later).

The oil tank 83 is mounted to the bottom of the housing 1a. The oilcirculated through the transmission is returned into the tank 83. Thebottom plate of the housing 1a has, on the side of the transmissionunit, an oil discharge port 84 through which lubricating oil isdischarged into the oil tank 83.

The transmission unit and the gear unit 20 are separated by apartitioning wall 85 of the housing. The wall 85 has holes 86 throughwhich lubricating oil in the gear unit 20 flows back into the oil tank83.

A strainer 87 and a relief valve 88 are provided in the oil tank 83.They are connected through passages 89 and 90 formed in the wall of thehousing la to the trochoid pump 81.

A passage 91 branches from the passage 90 and communicates with apassage 92 formed in the front part of the transmission unit.Lubricating oil is supplied through the passage 92 to the inner-diametersurface of the carrier 5, the support portions of the double cones 4,and the frictional contact surfaces of the double cones 4 and the inputring 7.

The lubricating oil in the oil tank 83 is sucked up through the strainer87 and the passage 89 into the trochoid pump 81 and then suppliedthrough the passage 90 into the passage 91. The oil pressure in thepassage 90 is regulated by the relief valve 88.

From the passage 91, the lubricating oil flows through a passage formedin the housing (not shown) into the passage 92 and then supplied to theparts in the friction type variable transmission unit.

The lubricating oil thus circulated through the friction type variabletransmission unit and the planetary gear unit 20 is returned through theholes 86 and the oil discharge port 84 into the oil tank 83. The oilreturned into the tank 83 is again sucked up by the trochoid pump 81 andsupplied to the various parts in the transmission. This cycle isrepeated.

The oil pump for sucking up lubricating oil is not limited to thetrochoid pump 81 but may be a gear pump or any other type of pump.

FIGS. 12 and 13 show another embodiment according to the third aspect ofthe invention.

In this embodiment, screw-in type throttle valves 94 and 95 are providedin the passage 92 formed in the front wall of the housing 1a.

The throttle valves 94 and 95 are setscrews 97 engaged in threaded holes96 intersecting the passage 92. By adjusting the lengths of the portionsof the screws 97 protruding into the passage 92, the sectional area ofthe passage 92, which determines the flow rate of lubricating oil, ischangeable.

A spray 99 is provided at an oil outlet 98 formed in the top wall of thehousing la and so as to communicate with the passage 92. It sprays thelubricating oil supplied from the passage 92 through the oil outlet 98.

By changing the sectional area of the passage 92 with the throttle valve94, the oil flow rate through the passage 92, i.e. the amount of oilsupplied to the spray 99, can be adjusted to an optimum level. The oilsupplied into the spray 99 is sprayed through the outlet 98 and supplieduniformly in the form of mist to the contact surfaces between the doublecones 4 and the drive cone 8 and the contact surfaces between the doublecones 4 and the input ring 7.

By adjusting the throttle valve 95, it is possible to regulate theamount of lubricating oil flowing into an output bearing 100. In theembodiment, screw-in type throttle valves are used. But bush typethrottle valves may be used instead. Also, valves other than throttlevalves may be used to adjust the sectional area of the passage 92.

The spray 99 may be one capable of spraying lubricating oil radiallywithin a wide angular range.

Industrial application

In the first aspect of the invention, the rotation preventive meansprevents the rotation of the carrier supporting the double cones whileallowing only its axial movement. The double cones, prevented fromrotating about the input shaft, operate stably.

By providing the stopper for restricting the axial movement of thecarrier and/or by providing the support shafts for the double cones withlarge-diameter portions to prevent the double cones from coming off ofthe shafts, it is possible to restrict the movement of double coneswithin a proper range. This makes it possible to prevent the doublecones from getting out of contact with the input or output shaft.

In the second aspect of the invention, the friction type variabletransmission can be stopped when there is no need to increase therevolving speed. This makes it possible to minimize the loss of enginepower. Also, it is possible to minimize the wear of the rotary membersin the transmission and thus to prolong its life.

By coupling the input shaft to the clutch through the rotationpreventive means which allows axial movement of the input shaft it ispossible to prevent the input shaft from interfering with the clutcheven if it moves axially, biased by elastic members. Thus, torque can betransmitted stably in the transmission.

In the third aspect of the invention, the lubricating oil in the oiltank is suctioned by the oil pump and supplied through the passageformed in the housing to various inner parts of the friction typevariable transmission unit and the planetary gear unit. Thus, they canbe lubricated stably.

Since the oil feed passage is formed in the housing wall, and the oilpump is mounted in the planetary gear unit, the entire transmission issufficiently compact in size, and yet it maintains a high speedincreasing capacity.

By controlling the flow rate of oil in the passage with a valve, it ispossible to distribute a proper amount of lubricating oil to variousparts in the transmission to lubricate them in an optimum way.

By providing the spray means for spraying lubricating oil in thehousing, it is possible to supply lubricating oil uniformly to variousparts in the transmission. This further improves the lubricationcondition in the transmission.

We claim:
 1. A friction type continuously variable transmissioncomprising an input shaft, an output shaft provided coaxially with saidinput shaft, a plurality of double cones kept in contact with both saidinput shaft and said output shaft so as to be movable in the axialdirection of said input and output shafts, a biasing means biasing saidinput shaft away from said double cones so that said double cones arepulled by said input shaft and said output shaft in opposite directions,a clutch coupled to said input shaft for, and a rotation preventivemeans provided between said input shaft and said clutch for preventingthe rotation of said input shaft relative to said clutch while allowingaxial movement of said input shaft.
 2. A friction type continuouslyvariable transmission comprising a friction type variable transmissionunit having a housing and an input member, a gear unit coupled to saidinput member and having an input shaft for transmitting the rotation ofsaid input shaft to said input member, an oil tank provided below saidtransmission unit and said gear unit for collecting lubricating oilcirculated through said transmission unit and said gear unit, and an oilpump mounted on said input shaft of said gear unit for suctioning thelubricating oil in said oil tank, said housing of said transmission unitbeing provided with a passage through which the lubricating oilsuctioned by said oil pump is supplied to said transmission unit andsaid gear unit.
 3. A friction type continuously variable transmission asclaimed in claim 2 and further comprising a valve in said passage forchanging the sectional area of said passage.
 4. A friction typecontinuously variable transmission as claimed in claim 3 wherein alubricating oil outlet is formed in a top wall of said housing andconnected with said passage, and wherein a spray means is provided atsaid oil outlet for spraying lubricating oil into said housing.
 5. Afriction type continuously variable transmission as claimed in claim 2wherein a lubricating oil outlet is formed in a top wall of said housingand connected with said passage, and wherein a spray means is providedat said oil outlet for spraying lubricating oil into said housing.
 6. Afriction type continuously variable transmission, comprising:an inputshaft; an output shaft; a carrier slidably mounted around said outputshaft and movable in the axial direction of said input shaft; aplurality of double cones connected with both said input shaft and saidoutput shaft for transmitting the rotation of said input shaft to saidoutput shaft, said plurality of double cones being mounted with saidcarrier such that movement of said carrier in the axial direction movessaid double cones in the axial direction and changes the revolving speedof said output shaft; and means for preventing rotation of said carrierabout said output shaft while allowing axial movement of said carrieralong said output shaft; wherein said carrier comprises support shaftsextending into holes in respective said double cones and rotatablysupporting said double cones, each of said support shafts having a freeend having a large-diameter portion that is larger in diameter than saidholes formed in said double cones.
 7. The friction type continuouslyvariable transmission of claim 6, wherein said rotation preventive meansfurther comprises a stopper restricting axial movement of said carrier.